Multi-path communication inherits from the multi-homing capability that is about supporting several IP addresses (IP is an acronym for “Internet Protocol”) to reach a given network endpoint. Problems and issues to address in multi-path technology are well known. For example, when using multiple paths to transmit information packets from a first endpoint to a second endpoint, the first endpoint must use a packet distribution strategy for balancing the data packets among the available paths linking the first and second paths. The aim of such a strategy is to select paths depending on the application (type of data) running in such endpoints and on the paths characteristic/status. The latter must be consistent with the real network state and is therefore maintained up to date through continuous measurements
Depending on the application and at least for video delivery, the following parameters are commonly used to characterize a path: bandwidth, jitter, delay. These parameters can be measured through an end-to-end measurement method. This may not be trivial as the measurement process must not perturbate the data transfer. Hereinafter, the bandwidth which is a parameter describing the ability of a path to deliver an amount of data during a time duration is the main interest and later the expression “bitrate” will be preferably used rather than the expression “bandwidth” which are considered as equivalent.
For measuring such parameters an end-to-end transport protocol like for example Stream Control Transmission Protocol (SCTP) or TCP may measure the available bitrate from a Round-trip-time (RTT) measurement, which is considered as being equal to a difference between the time of sending of a data packet by the first endpoint to the second endpoint and the arrival time of an acknowledgment packet sent by the second endpoint to the first endpoint, said acknowledgment being sent by the second endpoint immediately after it receives said data packet.
However one showed that the strategies for sending acknowledgment of data packets can affect the overall transmission as, for example in SCTP, where sending the acknowledgement of data packet through the fastest available path speeds up the overall transmission. If such a strategy is used, one cannot guaranty the acknowledgment comes back through the same path than the data packet itself. Then, using the acknowledgment of data for evaluating the Round-trip-time wouldn't be pertinent.
The problem is then:how to measure frequently the available bitrate on a path without generating a high overload and in combination with a strategy of acknowledgment path selection used for managing the data delivery?
One of the goals of the present invention is to solve that problem.